package topcoder.srm585;

import java.util.Arrays;

public class TrafficCongestionDivTwo {
	public long theMinCars(int th) {
		if (th <= 1)
			return 1;
		long[] res = new long[th + 1];
		Arrays.fill(res, -1);

		res[0] = res[1] = 1;

		for (int i = 2; i <= th; i++) {
			res[i] = (long) Math.pow(2, i - 1) + res[i - 2];
		}

		return res[th];

	}

	public static void main(String[] args) {
		TrafficCongestionDivTwo tc = new TrafficCongestionDivTwo();

		System.out.println(tc.theMinCars(60));

	}

}
